High Ammonia Nitrogen And Low Carbon Nitrogen Ratio Experimental Study Shortcut Nitrification Of Wastewater Treatment

Short-cut nitrification is defined as ceasing the reaction at NO2-N product phase by controlling reaction conditions. Anaerobic ammonium oxidation (ANAMMOX) process combined with short-cut nitrification process is considered to be a more economic nitrogen removal method compared with traditional nitrification denitrification process. As a pretreatment process of ANAMMOX, short-cut nitrification must attain partial nitritation effluent composed of NO2-N and NH3-N withinconcentration ratio ranges ofl to1.5. Sequencing batch reactors (SBRs)waschosen as short-cut nitrification reactors to study the influencing factors of short-cut nitrification and analyze the treating applicability and economy of livestock wastewaterby using artificial wastewater andbiogas slurry from swine wastewater digestion as influentrespectively.The influenceincluding DO cendentration, influent pH value, temperature and COD/TN ratio on short-cut nitrification process were studied by changing control parameters and influent conditions. The experimental results showed that NH3-N conversion and NO2-N accumulation efficienciesincreased and decreasedrespectively with the increase of DO concentration and decrease of influent pH value. Short-cut nitrification process would be well runin treating artificial wastewater under ambient temperature (T=25℃) condition if DO concentration and influent pH value being controlled in the range of0.3to0.8mg/L and8.3to8.5, respectively.Partial nitritation effluents would be achieved if aeration time controlled at6.5to7hours besides the above operation parameters.Short-cut nitrification could be affected significantly by temperature variation. NH3-N conversion efficiency was found to decrease from64.0%to26.9%when temperature dropped from25℃to12-18℃. NH3-N conversion efficiency decreased to8.8%when temperature dropped to2-8℃. The impactofinfluent COD/TN ratio on short-cut nitrification was less significantcompared with other influencing factors. The duration of COD removal needed to be prolonged whenCOD/TN ratio increased under the same influent NH3-N concentration.The experiments of treating livestock wastewater showed that short-cut nitrification process is applicabale in livestock wastewater treatment when influent NH3-N concentration ranged between200mg-N/L and400mg-N/L. The effluent water quality would be deterorited gradually under influent NH3-N concentration of800mg-N/L.The correspondingeconomic analysis showed that the treatment cost of ANAMMOX combined with short-cut nitrification process was lower compaered with traditional activated sludge and short-cut nitrification denitrification processes due to significant reducein power and chemical addition.Compared with the other two processes, this advantage in treatment costwould be more significantfor ANAMMOX process combined with short-cut nitrification processwhen dealing with higher pollutants concentrations in wastewater.